Rectenna For Energy Harvesting Research Articles

Microscale Chiral Rectennas for Energy Harvesting.

Wireless radiofrequency rectifiers have the potential to power the billions of "Internet of Things" (IoT) devices currently in use by effectively harnessing ambient electromagnetic radiation. However, the current technology relies on the implementation of rectifiers based on Schottky diodes, which exhibit limited capabilities for high-frequency and low-power applications. Consequently, they require an antenna to capture the incoming signal and amplify the input power, thereby limiting the possibility of miniaturizing devices to the millimeter scale. Here, the authors report wireless rectification at the GHz range in a microscale device built on single chiral tellurium with extremely low input powers. By studying the crystal symmetry and the temperature dependence of the rectification, the authors demonstrate that its origin is the intrinsic nonlinear conductivity of the material. Additionally, the unprecedented ability to modulate the rectification output by an electrostatic gate is shown. These results open the path to developing tuneable microscale wireless rectifiers with a single material.

Design of high-efficiency circularly polarized wideband energy harvesting rectenna using characteristic mode analysis

This paper presents a compact wideband rectifier system for wireless energy harvesting. The presented rectifier system is completed in two stages. In the first stage, a crescent-shaped wideband circularly polarized antenna (CPA) is designed to receive and transmit RF signals using characteristic mode analysis (CMA). And the CPA consists of a monopole antenna at the top and a slot antenna at the bottom, which control the higher and lower operating bands, respectively. In the second stage, a wideband rectifier is designed using a HSMS-2860 Schottky diode and a three-stage matching network. The HSMS-2860 Schottky diodes improve rectification efficiency at medium-power density, and the three-stage matching network effectively increase the operating bandwidth, filter out the output RF signal, and cancel out and stabilizes the impedance. To validate the proposed rectifier system, a crescent-shaped CP receiving antenna and a rectifier operating in C-band are fabricated, and the rectification performance is measured. The measurement results indicate that the proposed rectifier system harvests RF signals on the broadside and backside of the CPA over a wide input power range (8–13 dBm input power).

Energy Harvesting Rectenna Using High-Gain Triple-Band Antenna for Powering Internet-of-Things (IoT) Devices in a Smart Office

A new rectenna that can be utilized for sending/receiving data and scavenging radio frequency (RF) waves for linking and powering the Internet-of-Things (IoT) devices is proposed. The rectenna has three operating frequency bands; the lower frequency band is used for energy harvesting, and the other two frequency bands are assigned for data communication. It comprises a stacked four-layer antenna integrated with a voltage doubler rectifier. The antenna consists of a driven element, a planar reflector, and a planar director composed of a periodic structure of a square patch with a hexagonal slot in its center. The measurement results show that the proposed antenna covers 1.86–2.65, 2.84–3.64, and 5.34–6 GHz with an impedance bandwidth of 35%, 24.7%, and 11.64%, respectively. The antenna exhibits a high measured gain of 8.1, 8.9, and 9 dBi at 2.3, 3.5, and 5.7 GHz, respectively. The Industrial, Scientific and Medical (ISM) 2.45-GHz frequency band is selected for energy harvesting. Moreover, specific absorption rate (SAR) calculations are done for the antenna using the Hugo model to ensure lower absorption operation. The proposed antenna provides acceptable values of SAR; the values are under the safety standard limits for RF exposure. Then, a rectifier circuit is designed, fabricated, and tested separately. Finally, the rectifier is integrated with the proposed enhanced-gain antenna to produce a rectenna system. The rectenna presents a power conversion efficiency (PCE) of 69.7% and a dc output voltage of 1.9 V at an input power of 2 dBm. The PCE of the proposed rectenna is over 50% at a range of input power from −6.5 to 4.7 dBm.

Concomitance of radio frequency energy harvesting and wearable devices: A review of rectenna designs

Passing through the transformation of wood to coal then to oil and gas, we find ourselves fortunate to witness the next major transformation, which will lead us to the “New Energy Era.” Due to advancements in the field of electronics, energy harvesting has attracted great attraction from researchers and scientists to enhance portability and reliability with reduction in battery wastes. Moreover, wearable electronic devices are also becoming quite popular these days because of their usage in a broad range of applications like sports, health sciences, emergency, and so forth. In order to make sure smooth operation and to increase the working time span of these devices, it has become really important to bring wearable devices and radio frequency (RF) energy harvesting to the same platform. RF energy harvesting is one of the best suitable technology for wearable devices. The abundance of RF energy in surroundings and the ability of RF signal to penetrate buildings play an important role to empower wearable devices. One of the major challenges is to improve power conversion efficiency of wearable rectenna for energy harvesting due to requirements of less efficient bio-compatible materials for such antennas with conformability issues. This article mainly aims to present different wearable rectenna design techniques, reported over the years. It also presents a tabular comparison of rectenna performance in terms of power conversion efficiency and gains for diverse frequency bands, substrate materials, and conducting materials. In addition, this article also includes the challenges and obstacles in designing an efficient RF energy harvesting rectenna for wearable devices.

Experimental Verification of Gain and Bandwidth Enhancement of Fractal Contoured Metamaterial Inspired Antenna

In this work, a 2.5 GHz fractal contoured square microstrip antenna with four ring metamaterial structure, hereon referred to as optimized metamaterial inspired square fractal antenna (OMSFA), has been presented. This paper is an extension to the previously designed OMSFA [4] and aims to experimentally verify the enhanced gain and bandwidth of this antenna. The design and simulation of the proposed OMSFA was accomplished by using Ansys HFSS (v18.2). The end-to-end antenna spread area is 23 mm x 23 mm on a 46 mm x 28 mm x 1.6 mm FR4 substrate (εr = 4.4). The simulated OMSFA was fabricated using Nvis 72 Prototyping Machine and measured in an anechoic chamber facility using vector network analyzer. The antenna resonates with the deepest return loss at S11 of -39.5 dB in a broad bandwidth of 2.53 GHz from 2.265 GHz to 4.79 GHz with experimental verification. The OMSFA provides an enhanced gain of 8.81 dB at the desired frequency of 2.5 GHz. The simulation and experimental results of resonance, gain and radiation pattern are found to agree maximally. The fractional bandwidth offered by this proposed antenna is 72.28%. The experimental validation confirms enhanced gain-bandwidth performance in a wide resonance band. Hence, the OMSFA is well recommended for wireless and energy harvesting rectenna applications.

A broad band energy harvesting rectenna based on metamaterial complementary split ring resonator broadband antenna and BALUN rectifier

In this paper, we present a new design of a broadband energy harvesting rectenna. The rectenna consists of a compact bidirectional complementary split ring resonator broadband antenna and a broadband Balanced to unbalanced rectifier. The antenna design offers a 60% size reduction comparing to the conventional designs. The realized rectenna operates at a large bandwidth that includes four main harvestable ambient frequency bands (GSM-1.8 GHz, UMTS-2.1 GHz, WiFi-2.45 GHz and 4G-2.6 GHz GSM). The prototypes have been printed on 1.58 mm thickness FR4 substrate with a permittivity of 4.3. The design shows a higher efficiency compatibility at the lower power levels where it has reached 72% at −6 dBm input power.

Energy Harvesting Rectenna Design for Enhanced Node Lifetime In WSNs

With the rising popularity and advent of many services on Wireless Sensor Networks (WSNs), there is a compelling need to have energy-efficient solutions. The sensors and devices are powered by batteries whose life is limited, and at times it is impossible to replace the batteries, especially in remote applications. In such a scenario, Energy Harvesting (EH) stands as an undisputed candidate for enhancing the network lifetime. Radio Frequency (RF) energy is the most commonly available, ubiquitous, and reliable energy source among all the available energy sources. While RF signal carries both information and energy, EH is possible for long-distance and mobile environments. This work discusses initial research in the domain of EH in wireless networks via Radio Frequency (RF) signals. The paper presents an EH rectenna for energy harvesting over 2.45 GHz (Wi-Fi band). The receiving antenna is designed to pick up the radio signal in the RF range (2.45 GHz) from the free space. The four patch elements design has an antenna substrate made with RT with a dielectric constant of 2.2. The paper presents the simulation results of the basic parameters of the antenna, such as return loss, input impedance, bandwidth, gain, directivity, and efficiency. H-shaped slot antenna and modified H-shaped antenna (with circular slot) are designed with a gain of 8.24 dB and 8.32 dB, return loss of -10 dB and -16 dB, and bandwidth of 64.8 MHz and 868 MHz. The high gain, large bandwidth, properly matched impedance for minimum return loss, and high efficiency of the modified H-shaped patch antenna makes it eligible for energy harvestin.

MIIM-based optical log spiral rectenna for efficient IR energy harvesting

This study proposed, for the first time, a newly developed metal–insulator-insulator–metal (MIIM)-based log-spiral rectenna for energy harvesting applications. The designed resonant log-spiral antenna at 28.3 THz forwards the absorbed infrared (IR) electromagnetic (EM) radiations to the installed double insulator-based MIIM rectifying diode. The realized MIIM diode is formed by sandwiching the two insulators among the designed resonant antenna terminals (hot spot region). Antenna terminals are used as the electrodes of the rectifying diode. This novel approach ensures the maximum transfer of captured IR EM radiations by the antenna to the rectifying part with good impedance matching and thus increases the overall conversions efficiency. The study presents an in-depth analysis of the impact of the changing metal types (Au, Al, Ag, and Cu) and insulating materials (Al2O3, Cu2O, Ta2O5, TiO2, and ZnO with10 different formations) on the realized rectenna performance in terms of captured E-field enhancement, I/V, resistivity, and responsivity characteristics. It is found that the overall performance of the proposed double insulator-based rectenna system is better for the asymmetric configuration of Au- Al2O3- Cu2O –Cu and it exhibits 100% enhanced non-linearity as compared to MIM-based configuration.

Demonstration of resonant tunneling effects in metal-double-insulator-metal (MI2M) diodes

Although the effect of resonant tunneling in metal-double-insulator-metal (MI2M) diodes has been predicted for over two decades, no experimental demonstrations have been reported at the low voltages needed for energy harvesting rectenna applications. Using quantum-well engineering, we demonstrate the effects of resonant tunneling in a Ni/NiO/Al2O3/Cr/Au MI2M structures and achieve the usually mutually exclusive desired characteristics of low resistance ({R}_{0}^{DC} sim 13 kΩ for 0.035 μm2) and high responsivity (β0 = 0.5 A W−1) simultaneously. By varying the thickness of insulators to modify the depth and width of the MI2M quantum well, we show that resonant quasi-bound states can be reached at near zero-bias, where diodes self-bias when driven by antennas illuminated at 30 THz. We present an improvement in energy conversion efficiency by more than a factor of 100 over the current state-of-the-art, offering the possibility of engineering efficient energy harvesting rectennas.

A WIDEBAND ANTENNA ARRAY FOR RF ENERGY HARVESTING

In this paper, we introduce a wideband antenna array for RF energy harvesting from 3G/4G and Wi-Fi. The array consists of four parallelly linked wideband antenna elements and a metallic reflector to enhance gain and suppress back lobe radiation. In measurement, the antenna array possesses a wide bandwidth spanning from 1.6 GHz to 2.5 GHz, fully cover the three harvested bands, and the high gains between 13.5 dBi and 14 dBi. The antenna is employed in a multiband rectenna for energy harvesting and placed in the ambience. The rectenna was able to collect up to 0.27 mW power.

A wide input power range rectenna for energy harvesting and wireless power transfer applications

This article describes a novel rectifying-antenna design with extended input power range operating at 2.4 GHz for both ambient wireless energy harvesting and wireless power transmission (WPT) systems. The rectenna consists of a 2 × 2 fractal antenna array and a rectifier circuit with a high-power conversion efficiency (PCE) in a wide input power range. This circuit contains two conversion stages based on two different Schottky diodes, and a third stage that dissipates the unconverted input power, which can disturb the harvesting process. These three stages are controlled by a power management block based on circulators, that direct the input power to the adequate stage according to its power range. A prototype of the proposed harvesting system is fabricated and experimentally validated. The measurement results confirm the wide input power range behavior of the designed rectenna with a relatively constant and high PCE (between 58% and 67%) for a power density ranging from 4 to 252 μW/cm2. The proposed solution can be successfully used for both ambient energy harvesting and WPT systems.

A Review on the Development of Tunable Graphene Nanoantennas for Terahertz Optoelectronic and Plasmonic Applications.

Exceptional advancement has been made in the development of graphene optical nanoantennas. They are incorporated with optoelectronic devices for plasmonics application and have been an active research area across the globe. The interest in graphene plasmonic devices is driven by the different applications they have empowered, such as ultrafast nanodevices, photodetection, energy harvesting, biosensing, biomedical imaging and high-speed terahertz communications. In this article, the aim is to provide a detailed review of the essential explanation behind graphene nanoantennas experimental proofs for the developments of graphene-based plasmonics antennas, achieving enhanced light–matter interaction by exploiting graphene material conductivity and optical properties. First, the fundamental graphene nanoantennas and their tunable resonant behavior over THz frequencies are summarized. Furthermore, incorporating graphene–metal hybrid antennas with optoelectronic devices can prompt the acknowledgment of multi-platforms for photonics. More interestingly, various technical methods are critically studied for frequency tuning and active modulation of optical characteristics, through in situ modulations by applying an external electric field. Second, the various methods for radiation beam scanning and beam reconfigurability are discussed through reflectarray and leaky-wave graphene antennas. In particular, numerous graphene antenna photodetectors and graphene rectennas for energy harvesting are studied by giving a critical evaluation of antenna performances, enhanced photodetection, energy conversion efficiency and the significant problems that remain to be addressed. Finally, the potential developments in the synthesis of graphene material and technological methods involved in the fabrication of graphene–metal nanoantennas are discussed.

When Bessel Meets Fourier in the Power Representation of Energy Harvesting Rectennas

In this contribution, we develop a closed-form representation for the output DC power of a typical energy harvesting rectenna in terms of the input waveform. Taking into account the non-linearity of the rectifier, with operation in a spectrum band composed of $N$ channels, we present a compact general formula which relates the output DC power to the magnitude of the exponential Fourier-series coefficients of the periodic input signal, through summation of products of modified Bessel functions with different orders. In this way, one can easily compute the output power of the harvesting circuit by looking at the spectrum of the input signal. A tractable lower-bound for the output DC power is also proposed, and comparative results are provided.

Design Challenges of Rectenna for Energy Harvesting from Microwave Pollution

Design Challenges of Rectenna for Energy Harvesting from Microwave Pollution

A Miniature Energy Harvesting Rectenna for Operating a Head-Mountable Deep Brain Stimulation Device

This paper presents design, implementation, and evaluation of a miniature rectenna for energy harvesting applications. The rectenna produces DC power from a distant microwave energy transmitter. The generated DC power is then utilized to operate a head-mountable deep brain stimulation device. The rectenna consists of a miniature three-layer planar inverted-F antenna and a Schottky-diode-based bridge rectifier. The antenna has a volume of π × 6 × 1.584 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , a resonance frequency of 915 MHz with a simulated bandwidth of 18 MHz (907-925 MHz), and a measured bandwidth of 18 MHz (910-928 MHz) at the return loss of -10 dB. A dielectric substrate of FR-4 of εr = 4.5 and δ = 0.02 is used for simulation and fabrication of the antenna and the rectifier due to its low cost. An L-section impedance matching circuit is employed between the antenna and the rectifier to reduce the mismatch loss. The impedance matching circuit operates as a low-pass filter eliminating higher order harmonics. A deep brain stimulation device is successfully operated by the rectenna at a distance of 20 cm away from a microwave energy transmitter of power 26.77 dBm. The motivation of this paper includes creation of a deep brain stimulation device that operates indefinitely without a battery. From the application standpoint, the developed energy harvesting rectenna facilitates long-term deep brain stimulation of laboratory animals for preclinical research investigating neurological disorders.

Compact Wake-Up Module Design Based on an Energy-Harvesting Rectenna for Wireless Sensor Receivers

A new compact energy-harvesting module is proposed with compact design techniques. The rectifying circuit eliminates the band-pass filter and matching circuit, based on an active antenna concept and a direct matching technique. For exact circuit impedance, via holes are processed with precise fabrication techniques. The implemented circuit has achieved a circuit size reduction of 76.7%. The proposed system has been applied to a wireless wake-up receiver system with excellent operating performance.

Design of an Energy Harvesting Rectenna for Low-Power Wireless Sensor

This paper presents the design of a compact 2.45 GHz microstrip rectenna for wireless sensors’ power supply. In energy harvesting system, the ambient RF energy can be collected by the rectenna and converted to direct current, therefore, it can be applied to the power supply of low-power wireless sensor. Voltage doubling rectifier circuit and T-type microstrip impedance matching network are applied to this rectenna to increase the output voltage and the rectification efficiency. The antenna is fabricatied ​​by using double PCB board (FR4), and it is optimized by ADS to achieve the best performance. The measurement results show that the rectifier can reach the highest conversion efficiency of 78% when the load resistance is 320 Ω and the input power is 18 dBm. It also greatly improves rectenna’s conversion efficiency at lower input power when the input power is-20 dBm, which has great practical value for supplying low power consumption sensors.

Fabrication and Characterization of MIM Diodes Based on Nb/Nb2O5 Via a Rapid Screening Technique

Metal–insulator–metal (MIM) structures are gaining signifi cant attention due to their applications in varied electronic devices such as rectennas for energy harvesting, [ 1–4 ] high-frequency detectors/infrared photo-detection, [ 5–7 ] high-frequency mixers, [ 8–10 ] as well as applications in static memory and switching devices. [ 11 , 12 ] Ideally, for most of these applications, the MIM structure should exhibit current–voltage ( I–V ) characteristics with high asymmetry ( f ASYM > 1), strong nonlinearity ( f NL > 3), fast responsivity ( f RES > 7 V − 1 ), low hysteresis and low turn-on voltage (close to zero bias). [ 3 ] Despite the widespread utility and simple architecture of MIM devices, there is a signifi cant lack of understanding as to which materials properties produce the desired device performance. Although it is commonly stated that a high work-function difference ( Δ φ ) between the metal electrodes is responsible for high f ASYM and f NL , [ 3 , 5 , 7 ]